Hydraulic shock absorber



March 20, B. E OCQNNOR HYDRAULIC SHOCK ABSORBER Filed April l0, 1942 gee/vaca expansion chamber will contract the container bore I5.

Patented Mar. 20, 1945 i y y y g `"UINIITEl)V J ,y f Y Y ,2371,105'l `HYnrtzurrlcjsHocKfrissonner: t i `Bennaxzdui OkConnonBsualaeN. Lhassgnor 4 l iHomlaille-Hershey Corporation, Detrot,iMich f `rain rpurationfoi'fMchiga n i i i, i application April'ro, 1943,f'seriaiNoxrssncs y n u f "ancient, crass-996i t n My invention :relates 'to hydraulicf'shockMab- Wpacking material |19 .in the -cylinder#head around sorbers, particularly `toi-the directfactingfpiston "the jpisto'n rod prevents leakage type in-which "a'piston'isreciprocal'in a "cylinder "Ihe piston Pghas Vthe -bore 20 rin the firmer -end and" has a piston'frod extending therefrom `Iouto'fwhich 1is threaded the-annular Valvefseatnem- 'wardly through one 'endoffthe-jcylinder. With ber `2| terminatingWin-theannularjvalve'seat -or thistype of 4shock "absorbertan"expansion chamedge22. The seat is engageable by thefvfannula-r Vberisrusually` provided for receiving thefhydraulic valve disk 2 3 which has *theannularffstern P24 ex- 'fuid displaced-bytheipiston 'rod'whenfthetrodi-is tending therefrom in to la sleeve .25, this sleeve shifted' inwardlyfor `movement "offthepis'ton y"in having fthe flange l2li Lfitting in the seat imember `the cylinder. "Heretoiore'V such Vexpansion 'charn- .10 2 I and 4'slabbed off Lto provide passageway/i121'- the bers have Vu suaillyfbeenonly partially 'flledfdur- `valve vstem Abei-ng isecured to the sleeve asjby iingbpera'tionbf :the Lshockl'absorber fso"-1ihat-'ai`r 'rneansfof-apinZ-B.lv f i i Y could fimix Awith the *hydraulic ffuid ito fcause "The'sleeveat-itsiinnerfendfhasthe'cross Lwall fbubblesfor-emulsication- 29withaport-fandwithin'thesleeveisf-thebup -v l"l'hesimportant "'ob'ject Aof *my jinventionlistofu Valve ifpressedby `as ,pring "32 with its @bottom i 'preventa'ccessofairtofthe hydraulic ffluidlinthe normally `seated against the inner `:encleof-Ithe i from and keepingtheshock-absorber'atfallitimes `stricted orifice '3 3 may `be `prcvided; @The .stem full'dffiiuid i '1 i f has the passageway 34 inlits side normally closed `@Afurfther object 4is'to-provideianfarrangement g4)"bytheicupvalve3l.` i in which an expansible and contractible iclosed A fshockabsbrbing Sping135 lin the Cylinder containerlfull of air Vvor `other suitable gas is bore=l5=lextends-betweenfftheplugilhandtheinplaced in the expansion chamber which is closed nerwend ofithe piston P and tends @to iholdsfthe and which, together with the working chambers piston in its outer position against the Shoulder in the cylinder, is full of hydraulic fluid so that, 25 36. The piston bore 20 is connected through upon inward travel of the piston and piston rod passageways 3l with the space 3B between the in the cylinder, the displaced fluid now into the outer end of the piston and the inner end of the for compression of the air or gas therein pro- The cylinder has a lateral extension 39 providportionate to the volume of fluid forced into the 30 111g 2 llner and expansion chamber 40 for dis expansion chamber, and which contracted coni placed hydraulic fluid this chamberatits inner tainer, upon release of the load on the shock abend being connected through a hole 4I with the sorbed, will expand and force the hydraulic fluid space 38 in the cylinder. The chamber 40 is back into the working chambers in the cylinder. closed by a cover 42, and a ller screw plug 43 Referring to the drawing: 35 allows filling of fluid for` the shock absorber cyli Figure 1 is a longitudinal section of a shock inder and the chamber 40. Within the chamber absorber; t y i is the compensator element 44`in the form` of a Figure 2 is an enlarged section of the valve ashollow container of expansible and contractible sembly on plane II-II of Figure l; and material, as, for example, rubber or other mate Figure 3 is a section on plane III-III of Fig- 40 rial having the characteristics of rubber. The ure 1. container maybe of any shape and is entirely On the Structure ShOWn, the cylinder l0 isinclosed and filled with air or other suitable gas ternally threaded at its outer end to receive a. under pressure greater than that of atmospheric plug H which forms a head and has at its outer pressure. This pressure may be obtained by end holes 0r DaSSageWai/S l2 by means `of which A5 filling in fluid into the chamber iunder prest may be secured in any suitable manner t0 surewhich will primarilycontract the container structure on lwhich the `shock absorber is to be 44 for subjection of the contained gas to corre` used. To seal this end 0f the Cylinder, a gasket spending compression.y After lling of the shock I3 0f Suitable material iS tightly Squeezed in the absorber and the chamber 40, the compensator 44 annular recess I4 in the plug; Y 60 will iioat to the top of the chamber to expose the The cylinder has the bore l5 in which the pishole or passageway 4I. t i ton P operates, the piston rod I6 extending When the shock absorber is subjected to a force through the smaller bore l1 and terminating in tending" to shift lthe piston inwardly infthe -eyian eye I8 for connection with a structure with inder bore l5, the spring 35 will resistsuchmove which the shock absorber is to be used. Suitable liliy ment. If this movement is comparatively slow,

ture, the compensator correspondingly expands because of the initial compression it has been subjected to when the shock absorber was initially the compensator 44 for contraction thereof equal Y to the volume of the displaced uid. yIf the inward movement of the piston in the cylinder is' comparatively rapid or sudden, the pressure will' filled. The fluid at all times lls all available space in the shock absorber so that all air is excluded, and there consequently can beno bubbles in the fluid or emulsification which would materially interfere with the efcient operation of the shock absorber. B y my invention I have thus materially increased the eciency of shock absorber structures of the type referred to.

' I do not desire to be limited to the exact arrangment and operation shown and described, as

be sufficient to unseat the valve 23'against the. Y

resistance of the spring 45, so that the displaced iluid may ilow through the passageways 21 past the unseated valve 23 and into the expansion chamber 40 for contraction of thelcompensator 44. The valve 23 thus functions as a blow-off valve. If desired, 'the .restricted orice in the cup valve 3l may be omitted so that the valve 23 formsthe sole means for'controlling the flow of thedisplaced iiuid from the high pressure side of the cylinder to the low pressure side and into 4the expansion "chamber 4l).

When the pressure on the shock` absorber is released the spring 35 will shift the piston out `toits normal position,rthe pressure ofthe'uid atthe outer side of the piston then opening the valve 3| against its spring 32 for `comparatively `free flow of the fluid to the inner end of the cyl- -inder bore. n lthe piston and its stem, the pressure in the ex- During such outward movement of pansion chamber 4i! will be relieved and the compensator 44 will correspondingly expand to its Ioriginal shape and will assist the ow of the iiuid when the fluid contracts due to falling temperachanges and modications may be made without departing from the scope of the invention.

I claim as follows:

*A hydraulic shock absorber of the direct acting type comprising a cylinder, a piston movable in said cylinder and having a rod extending therefrom to the exterior of the cylinder, valve meansv controlling the flow of the displaced fluid fromrone side of the piston to the other,'a compensating elementvin the form of a closed expansible and contractible container lled with compressible and expansible medium,'sad cylinder being full of hydraulic uid in which said compensating element is immersed and said hydraulic fluid having been forced into said cylinder when the piston rod is Withdrawn and under a pressure l sumciently greater than atmospheric pressure for initialcompression and contraction of said compensating element by the fluid when said piston vis withdrawn whereby upon contraction and reduction in volume of the fluid in response to ymaximum anticipated temperature drop said compensating element may expand to compensate for such fluid volume reduction, said compensating element being compressed and contracted beyond its initial compression-and contraction when said piston rod moves into the cylinder.

BERNARD E. OCONNOR. 

